const max = Number.MAX_SAFE_INTEGER

console.log(max)  // 9007199254740991


console.log(max+1)  // 9007199254740992
console.log(max+2)  // 9007199254740993
console.log(max+3)  // 9007199254740994

console.log(Math.pow(2, 53) == Math.pow(2, 53) + 1)    // true


const bigNum = 100000000000000000000000000000n

console.log(bigNum * 2n)  // 200000000000000000000000000000n
